Annual performance factor
The annual performance factor, or APF for short, is the specific value that provides information about the energy efficiency of heat pumps. The higher this factor is, the greater the energy efficiency. Good values start at an annual performance factor of 4.5, which means that the heat pump in question requires only part of the electricity for four and a half times the heating capacity. Values below an annual performance factor of 3.5 are generally not found in modern heat pumps and would rule out government subsidies that only reward heat pumps with good annual performance factors.
The annual performance factor is mainly calculated from the ratio of the electricity supplied for operation to the heat dissipated in relation to the year. Unlike the coefficient of performance (COP), which is calculated from the same factors, the APF is a real calculation of energy efficiency, which also takes into account the type of heat pump (brine, water or air), user behaviour and local conditions in order to obtain an accurate result.
